The Obama administration's chief weapons buyer left behind advice for President Donald Trump and Defense Secretary James Mattis: Beware of quick fixes to the cumbersome procurement system pushed by business types.

Frank Kendall, who stepped down last week after five years as undersecretary for acquisition, technology and logistics, also said that the Defense Department had finally succeeded in getting a handle on the cost overruns and production delays for the F-35 Joint Strike Fighter.

In a speech last week to the Center for Strategic and International Studies in Washington, D.C., Kendall said that his successor, who has yet to be named, should be wary of the quick fixes for acquisition that will inevitably come his way from Congress and industry.

"I am not a believer in acquisition magic. It's all about hard work and attention to detail," said Kendall, who also cautioned against naming someone to his job with a business background but no experience at the Defense Department or in military service.

Kendall, 67, a West Point graduate who left the Army as a lieutenant colonel, noted the unique culture of the military and the sometimes conflicting needs of the services that have to be balanced against the never-ending budget battles in Congress.

"Bringing somebody in who does not have the experience working in that environment I think is a disservice," he said. The military "brings with it some very interesting cultural things and so does this town. A great deal of complexity comes with that."

In a memo to all Defense Department uniformed and civilian personnel last week shortly after he was sworn in, Mattis made a commitment similar to that of all of his predecessors to "gaining full value from every taxpayer dollar spent on defense, thereby earning the trust of Congress and the American people."

Kendall said that gaining full value in getting weapons from design to the production line to troops can change drastically over time, depending on the mission. He cited the example of the heavy, armored Mine Resistant Ambush Protected, or MRAP, vehicles that were rushed into production to provide protection against the roadside bombs that were taking a heavy toll on troops in Iraq.

"MRAPs were the right thing to do, no doubt about it," and they saved lives and limbs in Iraq, Kendall said, but the "cost of speed [in production] is quality."

The Pentagon quickly learned that the MRAPs purchased for Iraq were not well suited for the terrain in Afghanistan, and new versions had to be designed and produced. The lesson learned was that "there are times when you want to do rapid acquisition, but it's not a panacea," Kendall said.

He has summarized his acquisitions experiences in a government book called "Getting Acquisition Right." The book's cautionary message is: "We spend a lot of time trying to devise acquisition strategies that will effectively incentivize industry to deliver more of whatever the government wants.

"Industry has two priorities. In order of importance, they are to (1) win contracts, and (2) make money on them. The first is a prerequisite to the second. Government people should never lose sight of the fact that these imperatives always motivate industry. We can use them to get better results, but we need to be careful about unintended consequences."

Kendall said he is concerned about the unintended consequences that could come from the new administration bringing in acquisition managers with agendas that come from outside the Pentagon. "I'm not sure how it's going to work out," he said. "I can see it going in a good way or a bad way."

The results could be problematic if the new administration "brings in outsiders who have no idea how the Pentagon works, how the defense industry works. I'm a little nervous that might happen in this administration."

Kendall acknowledged that his legacy as Pentagon acquisitions chief will likely be highlighted by his quip some years ago on the problems with the F-35. He said they were the result of "acquisition malpractice."

The original sin of the F-35 acquisition process? "We started production before we had a stable design," he said.